Western Snowy Plovers and California Least Terns on Rancho Guadalupe Dunes Preserve, Guadalupe CA 2018 Final Report Prepared for: The County of Santa Barbara Santa Barbara, California Prepared by: Thomas E. Applegate and Sandra J. Schultz Wildwing Consulting Carlsbad, CA 92011 December 10, 2018 Table of Contents Summary........................................................................................................................................... 2 Introduction ...................................................................................................................................... 2 Study Area ........................................................................................................................................ 3 Methods............................................................................................................................................. 3 Snowy Plovers ................................................................................................................................ 3 California Least Terns ................................................................................................................... 4 Results ............................................................................................................................................... 4 Snowy Plovers ................................................................................................................................ 4 Nesting Population ...................................................................................................................... 4 Table 1. Estimated bi-weekly nesting pairs during the 2018 season. ........................................... 5 Figure 1. Snowy plovers counted on the RGDP range-wide census in 2001, and 2003 through 2018. ............................................................................................................................................. 5 Nesting and Productivity ............................................................................................................ 5 Figure 2. Number of snowy plover nests on RGDP in 2001, and 2003 through 2018. ................ 6 Table 2. The number and fates of snowy plover nests in 2018. .................................................. 6 Table 3. Mean clutch size 2003 through 2018.* ........................................................................... 6 Figure 3. Number of chicks hatched 2001 through 2018 (data not available for 2002 and 2006). ............................................................................................................................................ 7 Table 4. Nest initiations by month in 2003, 2004, and 2007 through 2018.* .............................. 7 Fledging and Brood Movement ................................................................................................. 7 Banded Plovers ............................................................................................................................ 7 Predators...................................................................................................................................... 8 Table 6. Number of snowy plover nests lost to predators on RGDP in 2001, and 2003 through 2018. ............................................................................................................................................. 8 Least Terns ..................................................................................................................................... 9 Table 8. Least tern nests, fates, and chick and fledgling numbers from 2001 - 2018.* ............. 10 Human Activities Affecting Plovers and Terns ........................................................................... 10 Discussion ....................................................................................................................................... 11 Management Recommendations .................................................................................................. 13 Literature Cited ............................................................................................................................. 14 Appendix 1. Snowy plover and least tern nest locations and fates during the 2018 breeding season. ......................................................................................................................................... 15 Appendix 2. Number and percent of snowy plover nests and their fates from 2001-2018.* ..... 16 1 Summary This report summarizes the 2018 Western snowy plover (snowy plover, plover) and California least tern (least tern, tern) breeding season monitoring on Rancho Guadalupe Dunes Preserve (RGDP). RGDP is owned and operated by the County of Santa Barbara (County). Monitoring was conducted by Thomas Applegate (Wildwing Recovery Permit # TE-823990-4) under contract to the County of Santa Barbara. This was the twelfth season Wildwing conducted the monitoring at RGDP. Sixty-two plover surveys were conducted between March 5 and August 27, 2018. The first known snowy plover nest was initiated on approximately March 25 and the last on July 12. Fifty-nine nests were found, and the fates of 50 were determined. Thirty nests hatched at least 1 chick, 16 were lost to predators, 2 were abandoned, 2 were destroyed by unknown causes, and the fates of 9 nests could not be determined. Seventy-five chicks hatched from the 30 successful nests. The first known hatch occurred on approximately May 3 and the last on July 31. Color banding of chicks did not occur so chick survival rates could not be determined. Least tern monitoring was conducted concurrently with snowy plover monitoring during the period breeding terns would be expected to be present. Terns were first observed on May 14 when 2 were seen flying over breeding habitat. The first known tern nest was located on June 20 and the last on July 15. A total of 11 nests were found, and the fates of 7 were determined. Five hatched 2 chicks each, for a total of 10 chicks for the season. Two nests were destroyed by coyotes, and the fates of the remaining 4 nests could not be determined. Of the 10 chicks hatched, 4 were confirmed to have fledged during the first half of August. Introduction Western snowy plovers (Charadrius nivosus nivosus) are small shorebirds measuring about 6 inches in length with pale brown to grey upper parts, a white belly and dark patches on the head and shoulders. The Pacific coast population nests near tidal waters of the Pacific Ocean on sand beaches and dunes, adjacent bays, and coastal river bars. The current known breeding range is from Damon Point, Washington to Bahia Magdalena, Baja California, Mexico. Snowy plovers that nest inland at alkaline lakes, ponds and river bars in the western states are not considered part of the coast population. The U.S. Fish and Wildlife Service (USFWS) designated the Pacific Coast population as “Threatened” on March 5, 1993 (Federal Register 58(42)12864-12874) under provisions of the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.). California least terns (Sterna antillarum brownii) are grey, white and black, and measure about 9 inches in length. They are the smallest North American tern. Least terns utilize suitable breeding habitat from Baja California, Mexico to the San Francisco Bay area in California. Nesting occurs on open sand, sand-shell beaches, and sand-fill sites where little vegetation exists. Breeding colonies are typically located within close proximity to waterways where birds forage for small fish. Least terns tolerate a considerable range in colony sizes. Some colonies have hundreds of birds, while some pairs nest alone or with a few other pairs. The species was given state and federal endangered status in 1970 (Federal Register 35(106)8491-8498) under the provisions of the Endangered Species Conservation Act of 1969 (16 USC 851 et seq.). Least terns are present in 2 their breeding areas from late May through August and are absent the remainder of the year. RGDP contains suitable breeding habitat for both snowy plovers and least terns. The site was monitored in 2001, and from 2003 through 2018. Prior to 2001 some non-intensive intermittent monitoring occurred, but no comparable data resulted from those efforts. Plovers have been documented nesting and wintering yearly and terns have nested 7 seasons since monitoring began. This report compares available and applicable yearly data collected since 2001 with the 2018 breeding season data (Applegate and Schultz 2003, 2004, 2007 through 2012, 2016 through 2018, Kelly 2014, 2015, Kelly and Applegate 2013, SRS 2006, Sandoval 2005, Persons 2001). Study Area RGDP encompasses approximately 592 acres of dune, scrub and riparian habitat immediately south of the Santa Maria River in northern Santa Barbara County. RGDP borders the Pacific Ocean for approximately 1.3 miles, extends inland up to 1.4 miles, and is part of the 18 mile long Guadalupe-Nipomo Dunes Complex. Suitable plover and tern breeding habitat extends north of RGDP through the Guadalupe Restoration Project, Guadalupe-Nipomo Dunes National Wildlife Refuge, and Oceano Dunes State Vehicular Recreation Area (Oceano Dunes SVRA). South of RGDP, contiguous breeding habitat exists on Gordon Sand and the Leroy Trust properties. The majority of RGDP is suitable breeding habitat for snowy plovers and least terns. Breeding habitat consists of a coastal beach strand bordered by open sand sheets